diff options
Diffstat (limited to 'fs/btrfs/qgroup.c')
| -rw-r--r-- | fs/btrfs/qgroup.c | 48 |
1 files changed, 44 insertions, 4 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index db680f5be745..f12dc687350c 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -940,6 +940,14 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info) int ret = 0; int slot; + /* + * We need to have subvol_sem write locked, to prevent races between + * concurrent tasks trying to enable quotas, because we will unlock + * and relock qgroup_ioctl_lock before setting fs_info->quota_root + * and before setting BTRFS_FS_QUOTA_ENABLED. + */ + lockdep_assert_held_write(&fs_info->subvol_sem); + mutex_lock(&fs_info->qgroup_ioctl_lock); if (fs_info->quota_root) goto out; @@ -1117,8 +1125,19 @@ out_add_root: goto out_free_path; } + mutex_unlock(&fs_info->qgroup_ioctl_lock); + /* + * Commit the transaction while not holding qgroup_ioctl_lock, to avoid + * a deadlock with tasks concurrently doing other qgroup operations, such + * adding/removing qgroups or adding/deleting qgroup relations for example, + * because all qgroup operations first start or join a transaction and then + * lock the qgroup_ioctl_lock mutex. + * We are safe from a concurrent task trying to enable quotas, by calling + * this function, since we are serialized by fs_info->subvol_sem. + */ ret = btrfs_commit_transaction(trans); trans = NULL; + mutex_lock(&fs_info->qgroup_ioctl_lock); if (ret) goto out_free_path; @@ -1166,9 +1185,24 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) struct btrfs_trans_handle *trans = NULL; int ret = 0; + /* + * We need to have subvol_sem write locked, to prevent races between + * concurrent tasks trying to disable quotas, because we will unlock + * and relock qgroup_ioctl_lock across BTRFS_FS_QUOTA_ENABLED changes. + */ + lockdep_assert_held_write(&fs_info->subvol_sem); + mutex_lock(&fs_info->qgroup_ioctl_lock); if (!fs_info->quota_root) goto out; + + /* + * Request qgroup rescan worker to complete and wait for it. This wait + * must be done before transaction start for quota disable since it may + * deadlock with transaction by the qgroup rescan worker. + */ + clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags); + btrfs_qgroup_wait_for_completion(fs_info, false); mutex_unlock(&fs_info->qgroup_ioctl_lock); /* @@ -1186,14 +1220,13 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) if (IS_ERR(trans)) { ret = PTR_ERR(trans); trans = NULL; + set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags); goto out; } if (!fs_info->quota_root) goto out; - clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags); - btrfs_qgroup_wait_for_completion(fs_info, false); spin_lock(&fs_info->qgroup_lock); quota_root = fs_info->quota_root; fs_info->quota_root = NULL; @@ -1219,7 +1252,8 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) btrfs_tree_lock(quota_root->node); btrfs_clean_tree_block(quota_root->node); btrfs_tree_unlock(quota_root->node); - btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1); + btrfs_free_tree_block(trans, btrfs_root_id(quota_root), + quota_root->node, 0, 1); btrfs_put_root(quota_root); @@ -3141,6 +3175,7 @@ static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans, struct btrfs_path *path) { struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_root *extent_root; struct btrfs_key found; struct extent_buffer *scratch_leaf = NULL; struct ulist *roots = NULL; @@ -3150,7 +3185,9 @@ static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans, int ret; mutex_lock(&fs_info->qgroup_rescan_lock); - ret = btrfs_search_slot_for_read(fs_info->extent_root, + extent_root = btrfs_extent_root(fs_info, + fs_info->qgroup_rescan_progress.objectid); + ret = btrfs_search_slot_for_read(extent_root, &fs_info->qgroup_rescan_progress, path, 1, 0); @@ -3360,6 +3397,9 @@ qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid, btrfs_warn(fs_info, "qgroup rescan init failed, qgroup is not enabled"); ret = -EINVAL; + } else if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) { + /* Quota disable is in progress */ + ret = -EBUSY; } if (ret) { |